When comparing S355J2 vs S355J2 N, many buyers, engineers, and project managers want to clearly understand how these two structural steel grades differ in performance, delivery condition, and application.
At GNEE, a professional steel manufacturer and exporter since 2008, we supply high-quality S355J2 and S355J2+N plates with strict quality control, full certification, and global project experience-helping you choose the right material and reduce procurement risks.
S355J2 vs S355J2 N – Definition and Basic Overview
S355J2 and S355J2+N are both structural steels defined under EN 10025-2, widely used in construction, bridges, offshore platforms, and heavy equipment. The "S355" indicates a minimum yield strength of 355 MPa, while "J2" refers to impact testing at -20°C.
The key distinction lies in the delivery condition:
- S355J2: Delivered in a standard condition (as-rolled or controlled rolled)
- S355J2+N (S355J2 N): Delivered in a normalized or normalized rolled condition
Normalization is a heat treatment process that refines grain structure, improving toughness, ductility, and consistency.
This difference directly impacts performance in demanding applications, especially under low temperatures or dynamic loads.
S355J2 vs S355J2 N – Chemical Composition Comparison
Chemically, both grades are nearly identical since they belong to the same standard.
Typical Chemical Composition (%)
| Element | S355J2 | S355J2+N |
|---|---|---|
| C | ≤ 0.20 | ≤ 0.20 |
| Si | ≤ 0.55 | ≤ 0.55 |
| Mn | ≤ 1.60 | ≤ 1.60 |
| P | ≤ 0.025 | ≤ 0.025 |
| S | ≤ 0.025 | ≤ 0.025 |
The difference is not in composition, but in heat treatment and resulting mechanical behavior.
S355J2 vs S355J2 N – Mechanical Properties Difference
Although both grades meet similar baseline mechanical requirements, S355J2+N typically offers more stable and reliable properties.
Mechanical Properties Table
| Property | S355J2 | S355J2+N |
|---|---|---|
| Yield Strength | ≥ 355 MPa | ≥ 355 MPa |
| Tensile Strength | 470–630 MPa | 470–630 MPa |
| Impact Test | -20°C | -20°C |
| Delivery Condition | As-rolled | Normalized |
Key Difference
- S355J2+N provides better toughness and uniformity
- Improved performance under low temperatures and welding conditions
S355J2 vs S355J2 N – Manufacturing Process Difference
The manufacturing route is where the real distinction lies.
S355J2 Production Process
- Hot rolling
- Air cooling
- No additional heat treatment required
S355J2+N Production Process
- Hot rolling
- Normalizing heat treatment (~900°C)
- Controlled cooling
- Normalization improves:
- Grain refinement
- Mechanical uniformity
- Resistance to brittle fracture
Factory workshop – plate rolling and heat treatment process
S355J2 vs S355J2 N – Heat Treatment and Microstructure
The most critical difference lies in the normalizing process.
What is Normalizing?
Normalizing involves heating steel above its critical temperature and then air cooling it.
This results in:
- Finer grain structure
- Improved mechanical consistency
- Enhanced toughness
S355J2 without normalization may have variable grain structure depending on rolling conditions, while S355J2+N ensures uniform internal properties.
Why Normalizing Matters in Real Projects
In large-scale projects like bridges or offshore platforms, inconsistent material properties can lead to structural risks. S355J2+N minimizes this risk by ensuring predictable performance.
S355J2 vs S355J2 N – Application Differences
S355J2 Applications
- General construction
- Machinery structures
- Non-critical load-bearing components
S355J2+N Applications
- Offshore structures
- Bridges and high-rise buildings
- Pressure vessels and heavy engineering
- Low-temperature environments
Steel plates in construction site – structural application
If your project requires higher reliability, especially in harsh environments, S355J2+N is the preferred choice.
S355J2 vs S355J2 N – Price and Cost Consideration
Due to the additional heat treatment process:
- S355J2+N is slightly more expensive
However, it reduces long-term risks and maintenance costs
From a lifecycle perspective, S355J2+N often provides better value.
S355J2 vs S355J2 N – How to Choose the Right Grade
When selecting between S355J2 and S355J2+N, consider:
- Operating temperature
- Load conditions (static vs dynamic)
- Welding requirements
- Project safety standards
Quick Selection Guide
- Choose S355J2 → for general, cost-sensitive projects
- Choose S355J2+N → for critical, low-temperature, or high-stress applications
When Should You Choose S355J2+N?
You should select S355J2+N when:
- Your project requires high toughness consistency
- Welding performance is critical
- The structure operates in low temperatures
- You need guaranteed mechanical reliability
If cost is a concern and the application is less demanding, S355J2 may still be a suitable option.
S355J2 vs S355J2 N – Advantages Comparison
Advantages of S355J2
- Lower cost
- Widely available
- Suitable for standard applications
Advantages of S355J2+N
- Superior mechanical stability
- Better performance in harsh conditions
- Higher safety margin for engineering projects
S355J2 vs S355J2 N – Equivalent Grades and Standards
Understanding equivalent grades helps global buyers source materials efficiently.
| Standard | Equivalent Grade |
|---|---|
| ASTM | A572 Gr.50 |
| DIN | St52-3 |
| JIS | SM490B |
| GB | Q355B |
Note: S355J2+N often aligns better with stricter international project requirements due to its normalized condition.
Why Choose GNEE for S355J2 and S355J2+N Steel Plates
At GNEE, we are more than just a supplier-we are a trusted partner:
- 18+ years manufacturing experience
- Annual capacity of 30,000 tons pressure vessels
- Full certification (EN, ASTM, ISO)
- OEM & ODM capabilities
- Global export to 150+ countries
We provide:
- Customized sizes and thickness
- Third-party inspection (SGS, BV)
- Fast delivery and competitive pricing
Steel plate packaging and shipping
FAQ – S355J2 vs S355J2 N
Is S355J2+N stronger than S355J2?
No, both have the same yield strength, but S355J2+N has better toughness and consistency.
Can S355J2 replace S355J2+N?
Only in non-critical applications. For demanding environments, S355J2+N is recommended.
What does "+N" mean in S355J2+N?
It indicates the steel is delivered in a normalized or normalized rolled condition.
Is S355J2+N better for welding?
Yes, due to its refined grain structure, it performs better during welding.
Does S355J2+N cost more?
Yes, due to additional heat treatment, but it offers better long-term performance.
S355J2 vs S355J2 N – Conclusion
In summary, the S355J2 vs S355J2 N difference mainly lies in the heat treatment process and resulting performance. While both grades share similar chemical composition and strength, S355J2+N provides superior toughness, consistency, and reliability-making it the preferred choice for demanding engineering applications.
If you are unsure which grade suits your project, GNEE's expert team is ready to help. Contact us today for a fast quotation, technical support, and customized steel solutions-your reliable partner for S355J2 and S355J2+N supply!
